/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.runtime.operators.coordination;

import org.apache.flink.runtime.jobgraph.OperatorID;
import org.apache.flink.util.SerializedValue;
import org.apache.flink.util.TemporaryClassLoaderContext;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Function;

/**
 * A utility to for dealing with the {@link OperatorCoordinator}.
 */
public final class OperatorCoordinatorUtil {

	public static Map<OperatorID, OperatorCoordinator> instantiateCoordinators(
			List<SerializedValue<OperatorCoordinator.Provider>> providers,
			ClassLoader classLoader,
			Function<OperatorID, OperatorCoordinator.Context> contextFactory) throws IOException, ClassNotFoundException {

		try (TemporaryClassLoaderContext ignored = TemporaryClassLoaderContext.of(classLoader)) {

			final HashMap<OperatorID, OperatorCoordinator> coordinators = new HashMap<>();

			for (SerializedValue<OperatorCoordinator.Provider> serializedProvider : providers) {
				final OperatorCoordinator.Provider provider = serializedProvider.deserializeValue(classLoader);
				final OperatorID id = provider.getOperatorId();
				final OperatorCoordinator.Context context = contextFactory.apply(id);
				final OperatorCoordinator coordinator = provider.create(context);
				coordinators.put(id, coordinator);
			}

			return coordinators;
		}
	}

	// ------------------------------------------------------------------------

	/** Utility class, not meant to be instantiated. */
	private OperatorCoordinatorUtil() {}
}
